linux/fs/proc/kcore.c
Arjan van de Ven 4b6f5d20b0 [PATCH] Make most file operations structs in fs/ const
This is a conversion to make the various file_operations structs in fs/
const.  Basically a regexp job, with a few manual fixups

The goal is both to increase correctness (harder to accidentally write to
shared datastructures) and reducing the false sharing of cachelines with
things that get dirty in .data (while .rodata is nicely read only and thus
cache clean)

Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-28 09:16:06 -08:00

406 lines
9.8 KiB
C

/*
* fs/proc/kcore.c kernel ELF core dumper
*
* Modelled on fs/exec.c:aout_core_dump()
* Jeremy Fitzhardinge <jeremy@sw.oz.au>
* ELF version written by David Howells <David.Howells@nexor.co.uk>
* Modified and incorporated into 2.3.x by Tigran Aivazian <tigran@veritas.com>
* Support to dump vmalloc'd areas (ELF only), Tigran Aivazian <tigran@veritas.com>
* Safe accesses to vmalloc/direct-mapped discontiguous areas, Kanoj Sarcar <kanoj@sgi.com>
*/
#include <linux/config.h>
#include <linux/mm.h>
#include <linux/proc_fs.h>
#include <linux/user.h>
#include <linux/a.out.h>
#include <linux/capability.h>
#include <linux/elf.h>
#include <linux/elfcore.h>
#include <linux/vmalloc.h>
#include <linux/highmem.h>
#include <linux/init.h>
#include <asm/uaccess.h>
#include <asm/io.h>
static int open_kcore(struct inode * inode, struct file * filp)
{
return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
}
static ssize_t read_kcore(struct file *, char __user *, size_t, loff_t *);
const struct file_operations proc_kcore_operations = {
.read = read_kcore,
.open = open_kcore,
};
#ifndef kc_vaddr_to_offset
#define kc_vaddr_to_offset(v) ((v) - PAGE_OFFSET)
#endif
#ifndef kc_offset_to_vaddr
#define kc_offset_to_vaddr(o) ((o) + PAGE_OFFSET)
#endif
#define roundup(x, y) ((((x)+((y)-1))/(y))*(y))
/* An ELF note in memory */
struct memelfnote
{
const char *name;
int type;
unsigned int datasz;
void *data;
};
static struct kcore_list *kclist;
static DEFINE_RWLOCK(kclist_lock);
void
kclist_add(struct kcore_list *new, void *addr, size_t size)
{
new->addr = (unsigned long)addr;
new->size = size;
write_lock(&kclist_lock);
new->next = kclist;
kclist = new;
write_unlock(&kclist_lock);
}
static size_t get_kcore_size(int *nphdr, size_t *elf_buflen)
{
size_t try, size;
struct kcore_list *m;
*nphdr = 1; /* PT_NOTE */
size = 0;
for (m=kclist; m; m=m->next) {
try = kc_vaddr_to_offset((size_t)m->addr + m->size);
if (try > size)
size = try;
*nphdr = *nphdr + 1;
}
*elf_buflen = sizeof(struct elfhdr) +
(*nphdr + 2)*sizeof(struct elf_phdr) +
3 * (sizeof(struct elf_note) + 4) +
sizeof(struct elf_prstatus) +
sizeof(struct elf_prpsinfo) +
sizeof(struct task_struct);
*elf_buflen = PAGE_ALIGN(*elf_buflen);
return size + *elf_buflen;
}
/*****************************************************************************/
/*
* determine size of ELF note
*/
static int notesize(struct memelfnote *en)
{
int sz;
sz = sizeof(struct elf_note);
sz += roundup(strlen(en->name), 4);
sz += roundup(en->datasz, 4);
return sz;
} /* end notesize() */
/*****************************************************************************/
/*
* store a note in the header buffer
*/
static char *storenote(struct memelfnote *men, char *bufp)
{
struct elf_note en;
#define DUMP_WRITE(addr,nr) do { memcpy(bufp,addr,nr); bufp += nr; } while(0)
en.n_namesz = strlen(men->name);
en.n_descsz = men->datasz;
en.n_type = men->type;
DUMP_WRITE(&en, sizeof(en));
DUMP_WRITE(men->name, en.n_namesz);
/* XXX - cast from long long to long to avoid need for libgcc.a */
bufp = (char*) roundup((unsigned long)bufp,4);
DUMP_WRITE(men->data, men->datasz);
bufp = (char*) roundup((unsigned long)bufp,4);
#undef DUMP_WRITE
return bufp;
} /* end storenote() */
/*
* store an ELF coredump header in the supplied buffer
* nphdr is the number of elf_phdr to insert
*/
static void elf_kcore_store_hdr(char *bufp, int nphdr, int dataoff)
{
struct elf_prstatus prstatus; /* NT_PRSTATUS */
struct elf_prpsinfo prpsinfo; /* NT_PRPSINFO */
struct elf_phdr *nhdr, *phdr;
struct elfhdr *elf;
struct memelfnote notes[3];
off_t offset = 0;
struct kcore_list *m;
/* setup ELF header */
elf = (struct elfhdr *) bufp;
bufp += sizeof(struct elfhdr);
offset += sizeof(struct elfhdr);
memcpy(elf->e_ident, ELFMAG, SELFMAG);
elf->e_ident[EI_CLASS] = ELF_CLASS;
elf->e_ident[EI_DATA] = ELF_DATA;
elf->e_ident[EI_VERSION]= EV_CURRENT;
elf->e_ident[EI_OSABI] = ELF_OSABI;
memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
elf->e_type = ET_CORE;
elf->e_machine = ELF_ARCH;
elf->e_version = EV_CURRENT;
elf->e_entry = 0;
elf->e_phoff = sizeof(struct elfhdr);
elf->e_shoff = 0;
#if defined(CONFIG_H8300)
elf->e_flags = ELF_FLAGS;
#else
elf->e_flags = 0;
#endif
elf->e_ehsize = sizeof(struct elfhdr);
elf->e_phentsize= sizeof(struct elf_phdr);
elf->e_phnum = nphdr;
elf->e_shentsize= 0;
elf->e_shnum = 0;
elf->e_shstrndx = 0;
/* setup ELF PT_NOTE program header */
nhdr = (struct elf_phdr *) bufp;
bufp += sizeof(struct elf_phdr);
offset += sizeof(struct elf_phdr);
nhdr->p_type = PT_NOTE;
nhdr->p_offset = 0;
nhdr->p_vaddr = 0;
nhdr->p_paddr = 0;
nhdr->p_filesz = 0;
nhdr->p_memsz = 0;
nhdr->p_flags = 0;
nhdr->p_align = 0;
/* setup ELF PT_LOAD program header for every area */
for (m=kclist; m; m=m->next) {
phdr = (struct elf_phdr *) bufp;
bufp += sizeof(struct elf_phdr);
offset += sizeof(struct elf_phdr);
phdr->p_type = PT_LOAD;
phdr->p_flags = PF_R|PF_W|PF_X;
phdr->p_offset = kc_vaddr_to_offset(m->addr) + dataoff;
phdr->p_vaddr = (size_t)m->addr;
phdr->p_paddr = 0;
phdr->p_filesz = phdr->p_memsz = m->size;
phdr->p_align = PAGE_SIZE;
}
/*
* Set up the notes in similar form to SVR4 core dumps made
* with info from their /proc.
*/
nhdr->p_offset = offset;
/* set up the process status */
notes[0].name = "CORE";
notes[0].type = NT_PRSTATUS;
notes[0].datasz = sizeof(struct elf_prstatus);
notes[0].data = &prstatus;
memset(&prstatus, 0, sizeof(struct elf_prstatus));
nhdr->p_filesz = notesize(&notes[0]);
bufp = storenote(&notes[0], bufp);
/* set up the process info */
notes[1].name = "CORE";
notes[1].type = NT_PRPSINFO;
notes[1].datasz = sizeof(struct elf_prpsinfo);
notes[1].data = &prpsinfo;
memset(&prpsinfo, 0, sizeof(struct elf_prpsinfo));
prpsinfo.pr_state = 0;
prpsinfo.pr_sname = 'R';
prpsinfo.pr_zomb = 0;
strcpy(prpsinfo.pr_fname, "vmlinux");
strncpy(prpsinfo.pr_psargs, saved_command_line, ELF_PRARGSZ);
nhdr->p_filesz += notesize(&notes[1]);
bufp = storenote(&notes[1], bufp);
/* set up the task structure */
notes[2].name = "CORE";
notes[2].type = NT_TASKSTRUCT;
notes[2].datasz = sizeof(struct task_struct);
notes[2].data = current;
nhdr->p_filesz += notesize(&notes[2]);
bufp = storenote(&notes[2], bufp);
} /* end elf_kcore_store_hdr() */
/*****************************************************************************/
/*
* read from the ELF header and then kernel memory
*/
static ssize_t
read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
{
ssize_t acc = 0;
size_t size, tsz;
size_t elf_buflen;
int nphdr;
unsigned long start;
read_lock(&kclist_lock);
proc_root_kcore->size = size = get_kcore_size(&nphdr, &elf_buflen);
if (buflen == 0 || *fpos >= size) {
read_unlock(&kclist_lock);
return 0;
}
/* trim buflen to not go beyond EOF */
if (buflen > size - *fpos)
buflen = size - *fpos;
/* construct an ELF core header if we'll need some of it */
if (*fpos < elf_buflen) {
char * elf_buf;
tsz = elf_buflen - *fpos;
if (buflen < tsz)
tsz = buflen;
elf_buf = kmalloc(elf_buflen, GFP_ATOMIC);
if (!elf_buf) {
read_unlock(&kclist_lock);
return -ENOMEM;
}
memset(elf_buf, 0, elf_buflen);
elf_kcore_store_hdr(elf_buf, nphdr, elf_buflen);
read_unlock(&kclist_lock);
if (copy_to_user(buffer, elf_buf + *fpos, tsz)) {
kfree(elf_buf);
return -EFAULT;
}
kfree(elf_buf);
buflen -= tsz;
*fpos += tsz;
buffer += tsz;
acc += tsz;
/* leave now if filled buffer already */
if (buflen == 0)
return acc;
} else
read_unlock(&kclist_lock);
/*
* Check to see if our file offset matches with any of
* the addresses in the elf_phdr on our list.
*/
start = kc_offset_to_vaddr(*fpos - elf_buflen);
if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
tsz = buflen;
while (buflen) {
struct kcore_list *m;
read_lock(&kclist_lock);
for (m=kclist; m; m=m->next) {
if (start >= m->addr && start < (m->addr+m->size))
break;
}
read_unlock(&kclist_lock);
if (m == NULL) {
if (clear_user(buffer, tsz))
return -EFAULT;
} else if ((start >= VMALLOC_START) && (start < VMALLOC_END)) {
char * elf_buf;
struct vm_struct *m;
unsigned long curstart = start;
unsigned long cursize = tsz;
elf_buf = kmalloc(tsz, GFP_KERNEL);
if (!elf_buf)
return -ENOMEM;
memset(elf_buf, 0, tsz);
read_lock(&vmlist_lock);
for (m=vmlist; m && cursize; m=m->next) {
unsigned long vmstart;
unsigned long vmsize;
unsigned long msize = m->size - PAGE_SIZE;
if (((unsigned long)m->addr + msize) <
curstart)
continue;
if ((unsigned long)m->addr > (curstart +
cursize))
break;
vmstart = (curstart < (unsigned long)m->addr ?
(unsigned long)m->addr : curstart);
if (((unsigned long)m->addr + msize) >
(curstart + cursize))
vmsize = curstart + cursize - vmstart;
else
vmsize = (unsigned long)m->addr +
msize - vmstart;
curstart = vmstart + vmsize;
cursize -= vmsize;
/* don't dump ioremap'd stuff! (TA) */
if (m->flags & VM_IOREMAP)
continue;
memcpy(elf_buf + (vmstart - start),
(char *)vmstart, vmsize);
}
read_unlock(&vmlist_lock);
if (copy_to_user(buffer, elf_buf, tsz)) {
kfree(elf_buf);
return -EFAULT;
}
kfree(elf_buf);
} else {
if (kern_addr_valid(start)) {
unsigned long n;
n = copy_to_user(buffer, (char *)start, tsz);
/*
* We cannot distingush between fault on source
* and fault on destination. When this happens
* we clear too and hope it will trigger the
* EFAULT again.
*/
if (n) {
if (clear_user(buffer + tsz - n,
tsz - n))
return -EFAULT;
}
} else {
if (clear_user(buffer, tsz))
return -EFAULT;
}
}
buflen -= tsz;
*fpos += tsz;
buffer += tsz;
acc += tsz;
start += tsz;
tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen);
}
return acc;
}